"Today we celebrate the hinge point of history with the inauguration of our first African-American president of the United States. We are so grateful to live in this land, a land of unequalled possibility where the son of an African immigrant can rise to highest level of our leadership," he said.

Play

null

"And we know today that Dr. King and a great cloud of witnesses are shouting in heaven," said Warren, the Christian pastor who leads the 20,000-member Saddleback Church in California.

Speaking to a nation whose religious face increasingly reflects the map of the world, Warren said, "Help us, O God, to remember that we are Americans, united not by race, or religion, or blood, but to our commitment to freedom and justice for all."

He asked God to "forgive us...when we fight each other" and "when we fail to treat our fellow human beings and all the earth with the respect that they deserve."

Watch live coverage of the Inauguration all day Tuesday beginning with "Good Morning America" at 7 a.m. ET and go to the Inauguration Guide for all of ABC News' coverage details.

Warren invoked the name of Jesus in prayer, despite comments from critics who had hoped the invocation would be more "inclusive" of Americans who are not Christian.

"He's a Christian pastor," Warren's spokesman Larry Ross told Fox News Monday. "He's going to pray the only kind of prayer he knows how to pray. He is going to pray consistent with his calling as an evangelical pastor."

'Give Us Clarity in These Difficult Days'

"And as we face these difficult days ahead, may we have a new birth of clarity in our aims, responsibility in our actions, humility in our approaches, and civility in our attitudes, even when we differ," said Warren, perhaps referring to the ongoing disagreements about who should lead the nation in the symbolic moment of prayer.

He also urged Americans to "seek the common good for all" for a "more prosperous nation and peaceful planet."

"We now commit our new president and his wife, Michelle, and daughters Malia and Sasha into your loving care, in the name of one who changed my life … Jesus," he said, ending with the Lord's Prayer, the bedrock of Christian worship.

Warren had been tight-lipped right up until he delivered the traditional kick-off prayer, refusing interviews with more than 100 media outlets, including ABCNews.com.

Warren, who angered critics with his socially conservative views on abortion and gay marriage, had urged his Orange County congregation to support California's Proposition 8 -- the successful campaign to ban same-sex marriage.

At that commemorative service, Warren again avoided controversy and borrowed a theme from the civil rights movement, "We Shall Overcome."

Over the weekend, about 100 gay rights supporters had marched and waved rainbow flags outside Warren's church in Lake Forest, Calif.

Problematic preachers like Warren have woven through the political life of Barack Obama, like a coat of many colors, all the way up to his inauguration as the 44th U.S. president.

First, firebrand Rev. Jeremiah Wright nearly derailed Obama's fight for the Democratic nomination. The uproar over his remarks from the pulpit such as "God damn America" and the U.S. being to blame for 9/11, prompted Obama to turn away from his former pastor and give a key speech on race and religion.

Then, the president-elect, who is a Christian, touched off a firestorm of controversy with Warren's selection.

As if to open the big tent even more, Obama picked V. Gene Robinson, the openly gay Anglican bishop from New Hampshire, to give the invocation at the start of inaugural events at the Lincoln Memorial on Sunday. Robinson had previously called Obama's choice of Warren a "slap in the face."

Gay rights advocates fumed over remarks Warren made to Beliefnet in December suggesting that if gay marriage were legal, why not incest, polygamy or "an older guy marrying a child?"

Conservative evangelicals were equally critical of Warren for accepting the inaugural invitation because of Obama's pro-choice abortion stance, just as they were when the president-elect joined a 2008 forum at Saddleback during the campaign.

But religious and even gay leaders are guardedly hopeful that this drama is yet another signal that Obama intends to rely on Lincoln's "team of rivals" approach to hear all points of view.

In the days before the inauguration, both preachers softened. When Robinson was named, Warren gushed to the New York Times that the president-elect had "again demonstrated his genuine commitment to bringing all Americans of goodwill together in search of common ground."

Warren, Robinson Rhetoric Softens

"I applaud his desire to be the president of every citizen," said Warren.

And Robinson echoed just last week, "Frankly, I think it is a magnificent, symbolic statement that Rick Warren and I will be praying for the new president and the nation. I think that's fantastic."

Gay activists say it is "heartening" to know that Robinson was included in the inaugural festivities, though his prayer wasn't televised in the live HBO special. But they were still uneasy about Warren's invocation, knowing the "symbolism" and "high profile" of that role.

"We are cautiously optimistic," said Joe Solmonese, president of the Human Rights Campaign, the nation's largest gay-rights group. Ultimately, he said, Obama is a friend of the lesbian, gay, bisexual, transgender community.

"The idea is that there is a place at the table for everybody, but at some point we draw the line, when you bring in people with incendiary views that say derogatory things about some Americans," he told ABCNews.com.

Some believe that Warren's centrist views -- supporting a broader agenda for evangelicals than just hot-button issues such as abortion and homosexuality -- might shift him to closer association with Obama.

Gay Marriage Non-Negotiable

This tempest in the Christian teapot over the invocation has no precedent.

"There used to be a Protestant a Catholic and a Jew," said Thomas Reese, senior fellow at Woodstock Theological Seminary at Georgetown University. "Now we get conservatives and liberals. I think it shows how politicized the religious community has become."

George Washington never had a prayer at his inaugural it was only in 1937 that the invocation became tradition. Franklin Roosevelt asked a Catholic supporter of the New Deal to join a protestant in prayer. Later, President Harry Truman added the first Jewish rabbi; and Dwight Eisenhower invited a Greek Orthodox minister.

Jimmy Carter cut it back to a Protestant and a Catholic. Ronald Reagan had only a Presbyterian at his first inaugural and later added a Catholic and a Jew. George H. W. Bush and Bill Clinton had Billy Graham, with Clinton adding another Baptist in 1997.

Billy Graham Never Uttered 'Jesus'

Prayer should be as "inclusive as possible," according to Reese. "The minister leading the prayer should not deny any aspect of his faith to please others, but he need not have every aspect of his faith expressed in his prayer."

The evangelist Graham never mentioned Jesus in his inaugural prayers.

By extending an invitation to both Warren and Robinson, Obama is "trying to reach out to all sorts of people and some of them don't like each other," said Reese.

"Warren and Robinson won't find common ground on abortion or gay rights, but Obama can bring them together in concern for the poor or health care or doing something for the victims of AIDS in Africa," he said.

In the two years since Obama has been invoking a message of common ground, a group of disparate voices -- both progressives and evangelicals -- has been shaping a shared agenda on social issues.

Ending the 'Culture Wars'

The proposal of shared goals -- "Come Let Us Reason Together Governing Agenda" -- is a call to Obama and to Congress to end what it calls the "culture wars."

Spearheaded by the progressive think tank Third Way, it includes religious leaders like the Rev. Joel C. Hunter and Dr. David Gushee, religion scholar Dr. Robert P. Jones and the religious group Faith in Public Life.

The agenda calls for agreement on four central issues: reducing abortions by increasing support for pregnant women and new families and adoption; protecting the rights of gays in the workplace, with an exemption for faith-based employers; renouncing torture; and supporting immigration reform.

"We are looking for principles in common: respect for human dignity, the golden rule, pragmatics and optimism are the common threads of the project," said Rachel Laser, director of Third Way's cultural program.

Asking Warren and Robinson both to share a role in the inauguration, is exactly the kind gesture this country needs, she said.

"Obama is a man of the big tent, letting more people come into the tent of progressive politics, expanding the tent to include someone like Warren and to simultaneously choose someone like the first openly gay bishop," said Laser told ABCNews.com.

Social Liberal Meets Evangelical

For Laser, who supports abortion rights and is Jewish, connecting with evangelicals like the mega-church pastor Joel Hunter, was daunting, but ultimately transforming.

She remembers meeting Hunter, pastor at Northland Church in Orlando, Fla., to show him her project. "Once you foster trust and create an environment that feels safe, it's not as hard as you think," she said.

Hunter, who opposed gay marriage and abortion, told Laser, her proposal "touched my heart." He is working on a pastor's manual, with research and scripture, to help his 12,000-strong parish understand the problems of workplace discrimination for gays, among other issues.

"We believe we are at a watershed moment in the country's history," Hunter said at a press conference announcing the agenda last week.

"The culture wars vilify those who are different from us by treating them as traitors and threats," said Hunter, a one-time president-elect of the Christian Coalition. "We can end the culture wars and both sides can advance without compromising our core basic values. It's a new form of maturity."